Rhombic Cutting Insert Layout for Faster Crankshaft Milling

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Solution Overview

Problem

Disc-shaped milling cutters for crankshaft and camshaft milling face challenges with large pitch between cutting inserts, limiting the number of inserts that can be mounted and causing heat retention due to chip sticking on rake surfaces, which reduces productivity and increases heat transfer.

Innovation Solution

A cutting insert with a rhombic basic shape and negative orientation, featuring acute corner angles between 70° and 85°, a chip groove on the top face, and a relief surface forming an obtuse inner angle with the top face, allowing for closer mounting and efficient chip evacuation, reducing heat retention and enabling more inserts to be mounted on the milling cutter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If cutting inserts are mounted with larger pitch to accommodate chip space and clamping access, then chip evacuation is improved and heat retention is reduced, but the number of cutting inserts that can be mounted on the milling cutter is limited, reducing productivity

Engineering Contradiction:
Improvenumber of cutting insertsVSAvoidheat retention
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The cutting insert is tilted relative to the radial direction of the milling cutter, introducing an angular dimension to the mounting configuration. This tilting allows the top face to be oriented at an angle between 5° and 30° relative to the radial direction, enabling closer pitch between inserts while maintaining adequate chip space through the angled chip groove geometry

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Instead of orienting the cutting insert with the top face parallel to the radial direction (conventional approach), the insert is inverted/tilted so that the top face forms an acute angle with the radial direction. This inversion allows the clamping hole to be accessed more easily and reduces the circumferential space required between inserts

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If cutting inserts are mounted with larger pitch to allow access to clamping screws, then ease of operation is improved, but the number of cutting inserts that can be mounted is reduced, lowering productivity

Engineering Contradiction:
Improveaccess to clamping screwVSAvoidnumber of cutting inserts
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The cutting insert is tilted relative to the radial direction of the milling cutter, introducing an angular dimension to the mounting configuration. This tilting allows the top face to be oriented at an angle between 5° and 30° relative to the radial direction, enabling closer pitch between inserts while maintaining adequate chip space through the angled chip groove geometry

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Instead of orienting the cutting insert with the top face parallel to the radial direction (conventional approach), the insert is inverted/tilted so that the top face forms an acute angle with the radial direction. This inversion allows the clamping hole to be accessed more easily and reduces the circumferential space required between inserts

Inventive Principle:
Principle #13The other way round (Inversion)

3Temperature

If chip groove is added to evacuate chips efficiently, then heat transfer is reduced, but the complexity of the cutting insert design increases

Engineering Contradiction:
Improveheat transferVSAvoidcutting insert design
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The chip groove is positioned specifically in the region where chips are generated and need to be evacuated, rather than adding complex features throughout the entire insert. The groove is formed at an angle between 10° and 45° relative to the radial direction, creating an efficient chip evacuation path with minimal additional complexity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The chip groove is oriented at an angle between 10° and 45° relative to the radial direction of the milling cutter, utilizing angular orientation to achieve efficient chip evacuation. This angular configuration allows chips to be directed away from the cutting zone effectively without requiring complex three-dimensional groove structures

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3456450B1Cutting insert and crank shaft milling tool
Publication Date: 2022.12.21 SANDVIK INTELLECTUAL PROPERTY AB
  • EP3456450B1 patent drawingFigure 1A
  • EP3456450B1 patent drawingFigure 1B~1D
  • EP3456450B1 patent drawingFigure 2A~2D

AI summary

The present invention is related to a cutting insert comprising a top face (1) and a bottom face (2) parallel to the top face (1), wherein four side faces (3) and four corner faces (3') extend between the top (1) and bottom faces (2), wherein at least one cutting edge (4, 4') is formed at an intersection of the top face (1) and at least one of the corner faces (3') and two of the side faces (3) connected to the corner face (3'), the top face (1) forming a rake surface, while at least an upper part of the corner face (3') and the two side faces (3) forms a relief surface (5, 5') connected to the cutting edge (4, 4'), The invention is also related to a disc milling tool including such cutting inserts. In order to reduce the cycle time for crank shaft milling, the cutting insert (10), characterized in that in a plan view on the top face (1), the cutting insert (10) is forming a basic shape of a parallelogram having two diagonally opposed corners (8) including an acute angle (ε1) between 70° and 85°, wherein at least one of the acute angled corners (8) comprises the corner face (3') providing a corner cutting edge (4') of said cutting edge (4,4'), that the relief surface (5) is forming an obtuse inner angle (ε1) with the top face (1) and that a chip groove (6) is formed in the top face (1) adjacent to and along the cutting edge (4, 4').